Extruded polyethylene-based resin foam sheets have been primarily used as a cushioning material or a packaging material by utilization of their cushioning properties. Further, such foam sheets have been also used in recent years as an interleaf sheet to be inserted between adjacent glass plates (such as glass substrates for image display devices such as liquid crystal displays, plasma displays and electroluminescence displays) for preventing formation of scars on the surfaces thereof during transportation. Foam sheets to be used as an interleaf sheet for glass plates are disclosed in, for example, JP-A-2007-262409 and JP-A-2012-20766.
JP-A-2007-262409 discloses an extruded polyolefin-based resin foam sheet having a thickness of 0.3 to 1.5 mm and an apparent density of 18 to 180 g/L. The foam sheet is described to show a small degree of sag and to allow easy removal thereof between glass plates by vacuum suction. It is additionally described that deposition of dusts on glass plates may be suppressed because the foam sheet contains a polymeric antistatic agent and has excellent antistatic property.
JP-A-2012-20766 discloses an extruded polyethylene-based resin foam sheet having a thickness of 0.2 to 1.5 mm, an apparent density of 20 to 60 g/L and a basis weight of 10 to 50 g/m2. It is described that, because the resin constituting the sheet has a bending modulus of at least 300 MPa, the foam sheet shows a small degree of sag in spite of its low apparent density and lightness in weight and has excellent usability as an interleaf sheet for glass plates.